ENGR 111 Lecture
18
Reading: Class notes
Howstuffworks
web site
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Case Study: Cell phone
z
How do those cell phones work?
z
Walk through a big picture study
{
Tie some of the concepts in communications
together
Cordless phones
z
Use a base station that is connected to the
telephone wire
z
The handset talks to the base station
which sends voice over telephone network
z
Handset – base station talk over
air/wireless channel
z
Limited to about 1000 feet
z
Uses 900 MHz or 2.4 GHz frequency band
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Cell phones/ mobile phones
z
Use similar ideas
{
A handset/cellphone that we carry
{
A base station nearby that picks up your phone
call and sends it over the network
{
Longer range more than 1000 feet
z
Need to stay connected as we move